The present invention relates to a clamp device for connecting a tarpaulin or the like to a movable beam assembly in a tarpaulin handling machine.
Tarpaulins are used for a variety of purposes, where they are exposed to wear, tear and dirty environments. Tarpulins are often very big and heavy, and a tendency towards even bigger sizes may be noted, for example tarpaulins with a width of 8 m or more and a length of 20 m or more.
There is a need to handle tarpaulins for washing or cleaning or for inspecting them on large backlit surfaces. In washing machines or inspection machines, the tarpaulin may be attached or connected to a beam assembly, which moves the tarpaulin mechanically through the machine.
Connecting devices are used for connecting the tarpaulin to the beam assembly. Examples of such connecting devices are hooks or clamps, in the latter case for example mechanical, spring-biassed clamps or pneumatically controlled clamps.
The requirements on such connecting devices are that they shall provide a safe connection in spite of the great weight of the tarpaulin (for example 600 kg or more), they shall be as easy to handle as possible, both for connection and for later disconnection, they shall be able to withstand the environmentally harsh conditions in a washing machine, and they shall be as uncomplicated and cheap as possible.
These requirements may be fullfilled by a clamp device according the invention having as its clamping member freely rotatable, eccentric roller adjacent a base member.
The edge of the tarpaulin is inserted in a vertical or inclined position between the eccentric roller and the base member, and this free insertion is admitted in that the roller rotates in the insertion direction. When the tarpaulin is freed, its weight will accomplish a backwards rotation of the roller, and by eccentricity of the roller, a clamping action on the tarpaulin is automatically obtained. The clamping force is increased with increased weight of the tarpaulin.
An improved clamping action between the roller and provided with a groove, which is coaxial with the roller and preferably is cylindrical, for cooperation with the roller.
The engagement of the roller with the tarpaulin may be improved in that the roller has a knurled, serrated or corrugated surface.
The roller may be arranged on a clamp arm pivotably mounted in the clamp device. In a practical case, the clamp arm is pivotably mounted on a beam assembly tube, on which the clamp device is attached. The pivotable arrangement of the clamp arm will enable an opening of the clamp device for releasing the tarpaulin at the end of its processing in the handling machine.
For controlling the pivoting of the clamp arm, it may be engaged with a control member, which is movable between a position, in which the clamp device is operative for connecting the tarpaulin, and a position, in which the clamp device may release the tarpaulin.
Practically, the clamp arm may have a shoulder for engagement with the control member, which is axially movable in the clamp device and has an inclined control surface.
When the shoulder is en engagement with the control surface, the control arm is held in the clamping position, and after axial displacement of the control member the control arm can be pivoted for disconnecting the tarpaulin.
Normally, several clamp devicesxe2x80x94in a practical case twelve clamp devicesxe2x80x94are arranged in a row on the beam assembly. The different clamp devices may in such a case be concurrently controlled in that the control members of the different clamp devices are connected by means of a common control rod, which preferably may be operated by means at the end of the beam assembly.